Method of producing a concentrate of chrome ores



Patented June 8, 1937 UNITED STATES PATENT OFFlCE Gustav Arnold,Wadenswil, Switzerland, assignor, by mesne assignments, to Eduard vonOrelli,

Zurich, Switzerland No Drawing. Application May 8, 1934, Serial No.

724,633. In Switzerland August 19, 1933 3 Claims. (01. 209166) usefulparticles of the ore the useless matrix takes part in the floating. Inorder to obviate this drawback the oxygen atoms on the surface of theore have been substituted by sulphur in order to obtain aneasier'floating capacity of the ores. The sulphurizing of the surface ofthe ore can, however, not be carried out with all the oxidized ores asthe degree of the sulphurization depends on the affinity of therespective metal to sulphur.

2o sulphurized may be mentioned by way of example: Au, CuSiOa, SnOz,PbO, PbOs, Pba04 ZnCOs, ZnQ, ZnSiOi, F8203, FeCOs FeO, Cr203, furtherall manganese-tungsten ores.

. According to the present invention the above mentioned drawback of thesimultaneous floating of the ore and matrix may be overcome withoxidized chrome-ores by preliminarily treating these ores with a complexheteropolyacid or its salts.

The term complex heteropolyacids is to be understood as referring toacids obtained by replacing in an oxygen bearing acid one or more atomsof oxygen by oxygen bearing acid radicals of which one at least is ofdifterent'chemical nature than the fundamental acid. By way of examplethe iollowing complex heteropolyacids may be mentioned: phosphomolybdicacids, phosphotungstic acids, and the like.

The following ores which cannot be Example 1 kilogram of crushed chromeiron ore is, in the presence of water, subjected to the action of 0.135gramme of phospho-molybdic acid, whereupon 0.8-1" gramme ofsodium-palmitate as collecting agent and 0.02 gramme of pine oil as afrothing agent is added. The latter stabilizes the froth in which theore collects free from the matrix. 0.1 gramme of waterglass is advisablein 1 a further addition, whereupon the floating process is carried outin the known manner.

Instead of phospho-molybdic acid or its salts phospho-tungstic acid maybe used in the above example. 15

I claim:

1. The method of producing a concentrate of chrome ores by means offroth-flotation which comprises treating oxidized chrome ores with asubstance selected from the group consisting of phosphomolybdic acids,phosphotungstic acids, and their salts, and subjecting the product thusobtained to flotation by means of usual froth flotation agents.

2. The method of producing a concentrate of chrome-ores by means offroth-flotation which comprises treating oxidized chrome ores with asubstance selected from the group consisting of phosphomolybdic acidsand their salts and subjecting the product thus obtained to flotation bymeans of usual froth flotation agents.

3. The method of producing a concentrate of chrome-ores by, means offroth-flotation which comprises treating oxidized chrome ores with asubstance selected from the group consisting of 35 phosphotungstic acidand their salts and subjectlng the product thus obtained to 'flotationby means or usual froth flotation agents.

GUSTAV ARNOLD.

